In usual injection molding methods excluding molding methods such as an injection compression molding method using a basically different molding principle, application of a high-pressure clamping force to a mold for clamping has been a so-called molding method of a common practice. On the other hand, from a viewpoint of global environmental protection such as emission reduction of carbon dioxide, resource saving and the like, energy-saving is in demand for industrial machines such as injection molding machines.
Thus, in order to respond to such a demand, the applicant has already proposed in Japanese Patent Laid-Open No. 2007-118349 an injection molding method with which the demand for energy-saving from the viewpoint of global environmental protection such as emission reduction of carbon dioxide, resource saving and the like can be satisfied by applying a pressure in a required amount at required time to a mold and which has an advantage that degassing in the mold during molding can be performed reliably and stably and the like. This injection molding method is configured such that in injection molding by injecting and filling a molten resin from an injecting device into a mold having a fixed mold and a movable mold supported by a mold opening/closing device, a gap (set interval) is set between the fixed mold and the movable mold into which the molten resin does not enter in the injection molding in advance, the mold is closed in a state in which the gap on the basis of the set interval is provided, and the molten resin is injected and filled into this mold from the injecting device, and also, position control of the movable mold is executed so that the set gap is fixed at least during the injection and filling.